The present invention relates to a drive means of an electro-photography process unit.
Referring to FIG. 1 for illustrating a conventional electro-photography process unit, the surface of a photo-sensitive drum 28 is uniformly charged with a constant voltage by an electric charger 25 and then exposed to the light of a lamp 24 reflected from an original document placed on a platen glass 21, so that an electrostatic latent image is formed on the photo-sensitive drum 28 corresponding to the image of the document. The light source may be a laser scanning unit, light emitting diode, etc. Thereafter, as the photo-sensitive drum 28 is rotated, the toner of a developer 27 is attracted to the surface of the photo-sensitive drum 28 so as to develop the latent image transferred by a transfer means 32 to a sheet of paper supplied by a supply roll 20.
The paper adhering to the photo-sensitive drum 28 by the electrostatic force is separated by a separator 33 therefrom. Then the paper is conveyed by a conveyor belt 30 to a fixing means 40, where the paper is heated and pressed between a heat roll 34 and pressure roll 35 to fix the toner, conveyed to a discharging tray 39.
The residual toner on the photo-sensitive drum 28 is removed by a cleaning blade 29 and the latent image is canceled by the light supplied from a pre-erase lamp array 37.
FIG. 2 reveals the photo-sensitive drum 28 and magnet roll 27b which are driven by drive means as shown in FIGS. 3A and 3B. A motor has a shaft provided with a gear 22 and pulley 22a. The gear 22 is to transmit the power of the motor via a train of gears 41, 42 and 43 to a drum gear 28a. Meanwhile, the power of the motor is also transmitted via a pulley 22a, timing belt 45, pulley 44, idle gear 43a, magnet roll drive gear 46 to the magnet roll 27.
Such conventional drive means is very complicated, requiring a large installing space and many parts, thus increasing the production cost.